linux-imx

/*

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * Authors: Waiman Long <waiman.long@hpe.com>

 */

​

/*

 * When queued spinlock statistical counters are enabled, the following

 * debugfs files will be created for reporting the counter values:

 *

 * <debugfs>/qlockstat/

 *   pv_hash_hops   - average # of hops per hashing operation

 *   pv_kick_unlock - # of vCPU kicks issued at unlock time

 *   pv_kick_wake   - # of vCPU kicks used for computing pv_latency_wake

 *   pv_latency_kick    - average latency (ns) of vCPU kick operation

 *   pv_latency_wake    - average latency (ns) from vCPU kick to wakeup

 *   pv_lock_stealing   - # of lock stealing operations

 *   pv_spurious_wakeup - # of spurious wakeups in non-head vCPUs

 *   pv_wait_again  - # of wait's after a queue head vCPU kick

 *   pv_wait_early  - # of early vCPU wait's

 *   pv_wait_head   - # of vCPU wait's at the queue head

 *   pv_wait_node   - # of vCPU wait's at a non-head queue node

 *   lock_pending   - # of locking operations via pending code

 *   lock_slowpath  - # of locking operations via MCS lock queue

 *   lock_use_node2 - # of locking operations that use 2nd per-CPU node

 *   lock_use_node3 - # of locking operations that use 3rd per-CPU node

 *   lock_use_node4 - # of locking operations that use 4th per-CPU node

 *   lock_no_node   - # of locking operations without using per-CPU node

 *

 * Subtracting lock_use_node[234] from lock_slowpath will give you

 * lock_use_node1.

 *

 * Writing to the "reset_counters" file will reset all the above counter

 * values.

 *

 * These statistical counters are implemented as per-cpu variables which are

 * summed and computed whenever the corresponding debugfs files are read. This

 * minimizes added overhead making the counters usable even in a production

 * environment.

 *

 * There may be slight difference between pv_kick_wake and pv_kick_unlock.

 */

enum qlock_stats {

    qstat_pv_hash_hops,

    qstat_pv_kick_unlock,

    qstat_pv_kick_wake,

    qstat_pv_latency_kick,

    qstat_pv_latency_wake,

    qstat_pv_lock_stealing,

    qstat_pv_spurious_wakeup,

    qstat_pv_wait_again,

    qstat_pv_wait_early,

    qstat_pv_wait_head,

    qstat_pv_wait_node,

    qstat_lock_pending,

    qstat_lock_slowpath,

    qstat_lock_use_node2,

    qstat_lock_use_node3,

    qstat_lock_use_node4,

    qstat_lock_no_node,

    qstat_num,  /* Total number of statistical counters */

    qstat_reset_cnts = qstat_num,

};

​

#ifdef CONFIG_QUEUED_LOCK_STAT

/*

 * Collect pvqspinlock statistics

 */

#include <linux/debugfs.h>

#include <linux/sched.h>

#include <linux/sched/clock.h>

#include <linux/fs.h>

​

static const char * const qstat_names[qstat_num + 1] = {

    [qstat_pv_hash_hops]       = "pv_hash_hops",

    [qstat_pv_kick_unlock]     = "pv_kick_unlock",

    [qstat_pv_kick_wake]       = "pv_kick_wake",

    [qstat_pv_spurious_wakeup] = "pv_spurious_wakeup",

    [qstat_pv_latency_kick]    = "pv_latency_kick",

    [qstat_pv_latency_wake]    = "pv_latency_wake",

    [qstat_pv_lock_stealing]   = "pv_lock_stealing",

    [qstat_pv_wait_again]      = "pv_wait_again",

    [qstat_pv_wait_early]      = "pv_wait_early",

    [qstat_pv_wait_head]       = "pv_wait_head",